We report on studies of four small forest passerines of Saipan, Mariana Islands, Micronesia, in order to characterize the ecological strategies employed in this threatened but virtually unstudied bird assemblage, and to provide a baseline for assessing shifts in foraging and microhabitat use that might follow reestablishment of extirpated populations. Data were gathered on microhabitat selection and foraging behavior, and limited observations are reported on wet-dry season shifts and annual changes in foraging. Two species were primarily canopy species, with one (Bridled White-eye, Zosterops conspicillatus) a live-leaf gleaner using smaller perches of taller trees, particularly Cynometra ramiflora, and the other (Micronesian Honeyeater, Myzomela rubratra) a flower prober using larger perches of taller trees. The remaining two species occupied the canopy and understory, with one (Rufous Fantail, Rhipidura rufifrons) an aerial forager and the other (Golden White-eye, Cleptornis marchei) a more generalized forager that selected larger perches of a wider variety of smaller trees. Hence, the species overlapped ecologically, but were differentiated in use of microhabitat space, including both structural and floristic components, and in manner of foraging. Comparisons of ecological overlap demonstrated that the two white-eye species were the most similar of the four, and that the Rufous Fantail and Micronesian Honeyeater were most dissimilar. Each of the four species also exhibited versatility in their ability to utilize the forest habitat. Such versatility is advantageous in a periodically typhoon-damaged system, although competitive release could have contributed to this versatility. Prior to reestablishment of prehistorically extinct populations, additional studies should address the degree to which species interactions might influence the outcomes of such efforts.